A Layered Caching Architecture for the Interference Channel

TL;DR

This paper investigates a layered caching architecture for the two-user Gaussian interference channel, proposing a separation strategy that optimally exploits caches at both transmitters and receivers, especially when receiver caches are large.

Contribution

It introduces a novel layered separation strategy that considers interacting bit pipes, improving upon natural separation approaches in interference channels.

Findings

Optimal degrees-of-freedom achieved by the proposed strategy

Separation is optimal when receiver caches are large

Exposes interacting bit pipes at the network layer

Abstract

Recent work has studied the benefits of caching in the interference channel, particularly by placing caches at the transmitters. In this paper, we study the two-user Gaussian interference channel in which caches are placed at both the transmitters and the receivers. We propose a separation strategy that divides the physical and network layers. While a natural separation approach might be to abstract the physical layer into several independent bit pipes at the network layer, we argue that this is inefficient. Instead, the separation approach we propose exposes interacting bit pipes at the network layer, so that the receivers observe related (yet not identical) quantities. We find the optimal strategy within this layered architecture, and we compute the degrees-of-freedom it achieves. Finally, we show that separation is optimal in regimes where the receiver caches are large.